The long term objective of this research is to examine factors that influence the language development process for children with severe communication disorders who use augmented language systems. In a series of two studies, one aim is addressed: to examine the effects varying degrees of symbol arbitrariness and extant speech comprehension skills have on the discrimination, learning, retention, and use of symbols for communication. Forty 6-8 year old children with severe communication disabilities, divided into two groups based on extant speech comprehension skills, will participate in two studies. Study 1 will examine the discriminability of two visual-graphic symbols sets, Blissymbols and Lexigrams. Using a computer-based instructional paradigm, Study 2 will examine symbol learning and retention over a two month period. Generalization to a communicative setting will also be assessed in Study 2. Findings from the two studies will permit a more precise mapping of the intrinsic and extrinsic factors that influence augmented language learning. In turn, these findings will permit the design, development, and implementation of more efficient and effective language interventions.